Identity and search names
- Common name
- Glowlight tetra
- Scientific name
- Hemigrammus erythrozonus
- Other names
- Hemigrammus gracilis
- Category
- Freshwater fish
- Group
- Tetras and characins
- Origin
- Essequibo and Courantyne drainage systems of Guyana and Suriname
- Review outcome
- PASSED
Environment and housing
- Environment
- Freshwater
- Care level
- Beginner to intermediate
- Adult size
- Usually 3–4 cm total length
- Expected lifespan
- About 3–5 years
- Minimum housing
- At least 75 L with open mid-water for a mature shoal
- Temperature
- 23–28 °C
- pH
- 5.5–7.5
- Hardness or minerals
- Soft to moderately hard; soft acidic water improves breeding reliability
- Salinity
- Freshwater
- Lighting
- Subdued lighting over a dark substrate
- Social structure
- Keep at least 10–12; a larger shoal is calmer and displays more naturally
- Placement or swimming zone
- Middle water
- Temperament
- Peaceful and gentle
- Compatibility
- Use small peaceful fish with matching feeding speed; avoid large angelfish, aggressive barbs and boisterous feeders
- Habitat structure
- Mature planted aquarium with dark substrate, tannin-stained or shaded margins and open central swimming room
Feeding and nutrition
- Diet
- Small insect larvae, worms, crustaceans and varied fine prepared foods
- Feeding frequency
- Offer tiny suspended meals once or twice daily; do not rely on food that falls rapidly to the bottom
Breeding and reproduction
- Breeding or reproduction
- Egg scatterer over fine plants or mops; adults should be removed because they eat eggs, which are sensitive to bright light
- Parental care
- No parental care
System demands
- Filtration
- Use mature biological filtration sized for the full adult group and feeding load, with intake protection where juveniles, long fins or small fish are present. Provide steady turnover without preventing normal swimming or resting.
- Aeration
- Maintain strong surface gas exchange and stable dissolved oxygen. Increase aeration during warm weather, medication, transport recovery, breeding crowding or any ammonia or nitrite event.
- Maintenance
- Test ammonia, nitrite and nitrate, remove waste from feeding and shelter zones, and perform regular temperature- and chemistry-matched water changes before nitrate or dissolved organics accumulate.
Detailed husbandry
- Identity scope
- This profile applies to Hemigrammus erythrozonus. Confirm trade identity and preserve breeder, supplier or locality records where relevant.
- Adult size and space
- Usually 3–4 cm total length. At least 75 L with open mid-water for a mature shoal. Plan around adult dimensions, activity, group size, aggression and waste production rather than sale size.
- Social structure
- Keep at least 10–12; a larger shoal is calmer and displays more naturally
- Placement or swimming zone
- Primary zone: Middle water. Keep that zone usable for movement, feeding and refuge.
- Feeding ecology
- Small insect larvae, worms, crustaceans and varied fine prepared foods
- Feeding plan
- Offer tiny suspended meals once or twice daily; do not rely on food that falls rapidly to the bottom
- Water stability
- Maintain 23–28 °C; pH 5.5–7.5; hardness/minerals: Soft to moderately hard; soft acidic water improves breeding reliability. Stable oxygenation and nitrogen-cycle control matter more than chasing one exact number.
- Adult projected load
- Plan capacity for Keep at least 10–12; a larger shoal is calmer and displays more naturally at the documented adult size (Usually 3–4 cm total length) in At least 75 L with open mid-water for a mature shoal. Include feeding intensity, territorial behaviour and breeding growth rather than counting sale-size juveniles.
- Filtration
- Use mature biological filtration sized for the full adult group and feeding load, with intake protection where juveniles, long fins or small fish are present. Provide steady turnover without preventing normal swimming or resting.
- Aeration
- Maintain strong surface gas exchange and stable dissolved oxygen. Increase aeration during warm weather, medication, transport recovery, breeding crowding or any ammonia or nitrite event.
- Maintenance
- Test ammonia, nitrite and nitrate, remove waste from feeding and shelter zones, and perform regular temperature- and chemistry-matched water changes before nitrate or dissolved organics accumulate.
- Habitat structure
- Mature planted aquarium with dark substrate, tannin-stained or shaded margins and open central swimming room
- Compatibility plan
- Use small peaceful fish with matching feeding speed; avoid large angelfish, aggressive barbs and boisterous feeders
- Breeding plan
- Egg scatterer over fine plants or mops; adults should be removed because they eat eggs, which are sensitive to bright light. Parental care: No parental care.
- Quarantine
- Quarantine new fish in a separate cycled aquarium with dedicated equipment. Match temperature and mineral chemistry gradually, confirm feeding and normal respiration, and never add transport water to the established aquarium.
- Welfare checks
- Maintain the stated adult space and social structure, verify feeding and intervene early when injury, exclusion, weight loss, abnormal respiration or altered behaviour appears. Bright bare aquariums suppress normal colour and confidence. Breeding eggs require dim conditions, and adults should not be left with the spawn.
- Biosecurity and release
- Never release fish, fry, eggs, aquarium water, sediment, plants or live foods into drains, dams or natural waterways. Confirm current Australian import conditions and South Australian possession, trade and movement rules before acquisition or transfer.
- Main risk
- Bright bare aquariums suppress normal colour and confidence. Breeding eggs require dim conditions, and adults should not be left with the spawn.
- Overridable warnings
- Bright bare aquariums suppress normal colour and confidence. Breeding eggs require dim conditions, and adults should not be left with the spawn. Any override must still preserve adult space, social welfare, stable chemistry, oxygen and filter capacity.
Welfare and risk
- Welfare checks
- Maintain the stated adult space and social structure, verify feeding and intervene early when injury, exclusion, weight loss, abnormal respiration or altered behaviour appears. Bright bare aquariums suppress normal colour and confidence. Breeding eggs require dim conditions, and adults should not be left with the spawn.
- Main warning
- Bright bare aquariums suppress normal colour and confidence. Breeding eggs require dim conditions, and adults should not be left with the spawn.
- Biosecurity
- Never release fish, fry, eggs, aquarium water, sediment, plants or live foods into drains, dams or natural waterways. Confirm current Australian import conditions and South Australian possession, trade and movement rules before acquisition or transfer.
Sources
Source note
Current identity or scope, husbandry, system-demand, welfare and Australian biosecurity evidence checked; active retired-source links removed; all AquaNexus wording is original.
- Eschmeyer’s Catalog of Fishes — Hemigrammus erythrozonus — Current accepted-name, synonym, family and habitat check
- Eschmeyer’s Catalog of Fishes — Hemigrammus erythrozonus — Accepted-name, synonym and taxonomic-placement cross-check
- Tropical Fish Hobbyist — Hemigrammus erythrozonus — Adult size, soft-water breeding and plant or mop spawning
- IUCN Red List search — Hemigrammus erythrozonus — Conservation-status and wild-provenance cross-check
- PIRSA — South Australian noxious fish list — Current South Australian possession and trade restriction cross-check
- DAFF — importing live ornamental fish to Australia — Current Australian live-fish import pathway and permitted-species warning